(2)
The original formula =1/2 (√ 3-1+√ 5-√ 3+√ 7-√ 5+√ 2013) × (√ 20/kloc-.
= 1/2 ×(√20 15- 1)×(√20 15+ 1)
= 1/2 ×(20 15- 1)
= 1/2 ×20 14
= 1007